Field of the Invention
The present disclosure relates to a liquid discharge method and a liquid discharge apparatus.
Description of the Related Art
When liquid is discharged by using a liquid discharge method typified by inkjet printing technology, the discharged liquid is column-shaped and includes a main droplet and a long droplet tail following and extending from the main droplet. While the liquid is being elected, the surface tension of the liquid causes the droplet tail to separate from the main droplet, so that the droplet tail turns into a small droplet (satellite droplet). The satellite droplet may be applied to a position different from that of the main droplet on a printing medium, leading to a reduction in image quality.
A liquid discharge method known in the art includes applying thermal energy to liquid through a heating surface to generate a bubble such that the bubble is allowed to communicate with an atmosphere during reduction of the volume of the bubble, thereby discharging the liquid (refer to Japanese Patent Laid-Open No. 11-188870). FIGS. 8A-8H are sectional views illustrating steps of liquid discharge to which this liquid discharge method is applied. According to this method, a trailing portion of discharged liquid has a velocity component pointing to a heating surface 11, so that the portion that may become satellite droplets tend to be separated from a main droplet within a discharge port. Consequently, the trailing portion does not tend to be ejected as satellite droplets from the discharge port.
According to the liquid discharge method disclosed in Japanese Patent Laid-Open No. 11-188870, the trailing portion of the liquid contacts the heating surface 11 (FIG. 8F) and the liquid is then separated at its part at which a velocity component pointing in a liquid discharging direction is substantially zero, so that the liquid is ejected (FIG. 8G). A trailing portion of the liquid that is being elected has a lower velocity than a main droplet of the liquid. Disadvantageously, there is still the likelihood that satellite droplets may be generated from the trailing portion separated from the main droplet of the liquid.